Improvement in steam rock-drills



1.0.GITHENS- Steam Ros-Drill.

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Um'rnn TATEs JOSEPH C. GITHENS,

0F NEW YORK,`N. Y.

IMPROl/EMENT IN STEAM ROCK-DRILLS.

` Specification forming Vpart of Letters Patent No. 164,990, dated June 529, 1875; application filed April 17, 1875.

To all whom it may concern:

the city, county, and State of New York, have invented a new and useful Improvement in Steam Rock-Drills, of which the following is a specification:

Figurel is alongitudinal section of the steam-cylinder, shield, and valve-chest of 4my improved drill. Fig. 2 is a cross-section of the same taken through the line x of Fig. 1. Fig. 3 isv a `rear View of the same, showing the long bolts.

Similar letters of reference indicate correspending parts. The object of this invention is to improve the construction of steam rock-drills, so asto make them stronger, more reliable in use, and less liable to getout of order.

The invention will be first fully described, and then pointed out in the-claims.

A is the steam-cylinder, which is constructed in the usual way, and moves up and down in ways in the shield B. The shield B is swiveled to the ordinary supporting frame-work in the usual way, and is strengthened by long bolts C, extending the whole length of the said shield B, and passing through lugs b formed upon its ends. The bolts C are extended upward beyond the upper end of the shield B, and to their upper ends are attached the ends of a cross-bar, D, to the center of which is swiveled the feed-screw E, which passes through a screw-hole in a lug, el, formed upon the rear part of the upper end of thecylinder A, so that, by turning the said screw, the cylinder may be moved down as the drill works its way into the rock, and moved up when the hole has been sunk to the required depth. The screw E is designed to be turned by a crank or hand wheel attached to its upper end. F is the piston that moves back andforth in the cylinder A as it is driven by the steam; The piston F is made long, and around its middle part is` formed a wide and shallow ring-groove, j", to serve as a steam-chest for the valve-shift` ing piston. G is the live-steam chest, which is covered with the cap H, in which slides the valve I, and into which the steam enters through the inlet-port g. a2 are passages leading from the end parts of the cavity of the cylinder A through the walls of said cylthe valve I is shifted. chest, which lis formed in the lower middle inder, and through the lower end parts of the cap H into the steam-chest G, and which become alternately inlet and outlet passages as J is the exhaust-steam part of the cap H, which becomes connected with the passages ce alternately as each passage c2 becomes an outlet-passage by the shifting of the valve l, andV from which the steam escapes through the exhaust-port j. To the' center of the valve I is attached the lower end of a pin, Ic, the upper end of which passes through a short longitudinal slot in the band L, and enters the solid middle part of the pis-V ton M. The piston M is placed in the upper part of the exhaust-steam chest J, and its ends enter cylindrical cavities in the upper end parts of the cap H, where they are surrounded by packing-ringsto prevent the pas- 1 sage of steam. The piston M is: made so much shorter than the cavity in which itworks as to give it the same movement or play as the valve I. The end parts of the piston M are made hollow, and through its sides at the ends of its solid middle part are formed a number of small holes or ports, on. In the end parts of the band L that surrounds the middle part of the piston M are formed two sets or circles of holes or ports, l. The ports m' l are exactly in line with each other, but the two sets of ports Z of the band L are at a greater distance apart longitudinally than the two sets of ports m', so that the two sets of ports may be alternately opened and closed by the longitudinal movement of the band L upon the piston M. c3 are small ports or passages leadlng from the end parts of the steamchest G into the cavity of the cylinderI A, so as to be opened as the groove f of the piston F comes opposite either of them, and closed as the end parts of said piston come opposite either of them. The ports c3 are at a distance apart greater than the breadth of the groove f', so that both of said ports a3 can never be open at the saine time. a4 are two ports or passages leading from the cavity of the cylinder A, near the ports d3, through the wall of said cylinder, and through the end parts of the cap H, and Opening into the cavity in which the piston M works at the ends of said piston M. When the piston F is at the upper end of its stroke, as shown in Fig. l, the steam enters through the upper passage d2 and forces the said piston downward. As the piston F approaches the lower end of its stroke, the lower ports a3 a4 are uncovered, and the steam passes through the port d4 to the lower end of the piston M, forcing the valve I upward and Yallowing the steam to pass through the lower passage a2 to the lower end of the piston F, and force the said piston F upward. As the piston M moves upward the forward edge of the band L strikes the upper end of the chest J, which stops the band L, while the piston M moves onward. This opens the upper set of ports l m', and allows the steam to exhaust from before the said piston M. As the piston F approaches the upper end of its stroke the upper ports d3 a4 are uncovered, and the valve I is again shifted, and so on until the entrance of the steam is stopped. N is the piston-rod, the inner end of which enters a hole in the forward end of the piston F, and is secured in place by a key. rlhe piston-rod N passes out through a stuffing-box in the end of the cylinder A, and upon its lower end is formed a head or enlargement, O, which is perforated in line with the axis of the pistonrod N to receive the shank of the drill P. The head O is slotted longitudinally upon one side to receive a key, Q, which ts into the said slot, and the inner edge of which is concaved to correspond with the perforation of the head O. Upon the outer side of the middle part of the key Q is formed a projection, which is notched transversely to receive the bend of the Ubolt It. The U-bolt R straddles the key Q, and its arms pass through the head O, and have nuts secured upon their ends. In

the face of the key Q, and in the inner surface of the head O directly opposite the said key, are formed longitudinal grooves, as shown in Fig. 5.

By this construction there will always be at least four points of bearing upon the drillshank, whether said shank be round or Octagonal, to hold the drill firmly, thus avoiding the necessity of turning o' thepctagonal steel of which the drills are usually made.

The inner edge of the middle part of the key Q is grooved or notched transversely beneath the bend of the U-bolt R, so that only the end parts of said key may bear upon the drill-shank to hold it more securely, and at the same time not too rigidly.

I am aware that guide-rods have been employed heretofore, but my bolts C are simply stay-bolts that remedy a'diiculty heretofore experienced in these machines. These bolts ordinarily extend only to the upper end of shield, lwhere the latter frequently breaks off. By extending these bolts C the whole length of shield this is prevented.

l. The combination, with shield B, having lugs b, of bolts C, extending its whole length, and the cross-bar D, to which the turning mechanism is attached, all arranged substantially as and for the purpose specified.

2. The valve-shifting piston M, made with hollow ends, a solid center and side ports, M and provided with a sliding band, L, made with ports Z, at a greater distance apart longitudinally than the ports m', in combination with the cap H ofthe steam-chest, the sliding valve I, the ports a3 d4 opening into the cylinder A, and the piston F, substantially as herein shown and described.

Josnrn o. Grrnnns.

Witnesses:

JAMES T. GRAHAM, T. B. MosHER. 

